Wireless communication devices may be referred to as, for example, mobile telephones, user equipments (UEs), wireless terminals, mobile terminals, mobile stations, cellular telephones, smart phones, laptops, tablet computers or phablets with wireless capability etc. Wireless communication devices are enabled to communicate or operate wirelessly in a Heterogeneous wireless communication system comprising multiple networks or Heterogeneous Networks (HetNet) with access nodes, such as a cellular communications network comprising Second/Third Generation (2G/3G) network, Long Term Evolution (LTE) network, Worldwide interoperability for Microwave Access (WiMAX) network, etc.
The wireless communication device in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, vehicle-mounted mobile devices, or any machine-type device, enabled to communicate voice and/or data via an access node with another entity, such as another communication device or a server in the wireless communication system.
The 5G, i.e. the 5th generation mobile networks or 5th generation wireless systems denotes the next major phase of mobile telecommunications standards beyond the current International Mobile Telecommunications-Advanced, 4G/IMT-Advanced standards. In the 5G wireless communication system, machine-to-machine communication or Machine-Type Communications (MTC) is one of the major research topics. Developing higher reliability and low latency of communications for Mission Critical-MTC is one important aspect, where ultra-low delay is a critical parameter. The Mission Critical-MTC concept should address design trade-offs regarding e.g., end-to-end latency, transmission reliability, system capacity and deployment, and provide solutions for design of wireless networks for different industrial application use cases.
One of the key design challenges is to achieve very low latency in the order of 1 ms for data transmission in order to enable new use cases such as real time control of industrial equipment or remote controlled vehicles. Existing wireless systems have in contrast been designed mainly with other use cases in mind, such as voice and internet access, where a latency of 20-50 ms is acceptable.
Existing wireless systems typically apply an approach where modulation and physical layer encoding is performed after available resources for transmission are known. In e.g. LTE, a user equipment (UE) receives a scheduling grant from the network which specifies radio resources or physical transmission resources that shall be used for a transmission. Parameters like transmission time and frequency, modulation and coding scheme are indicated by the scheduling grant and the UE performs the physical layer coding and modulation to fit the indicated radio resources.
The coding and modulation however take time, which makes it difficult to reach the low latency required for the transmission in the new use cases. The problem becomes more serious especially when a time critical message, e.g. an alarm message that needs to be transmitted immediately, is generated in a machine or device.